EQ UIPMENT NEWS requirements in the low pressure range and is distinguished by high safety s t a n d a r d s . A mechanically a c t u a t e d 4-layer sandwich diaphragm design of pure PYFE is the heart of this m e t e r i n g p u m p series. It is resistant against nearly all chemicals which must be metered a n d c a n n o t be d a m a g e d by s o l v e n t s or o t h e r d i f f u s i n g f l u i d s . T h i s p a t e n t e d d i aphragm design gives a service life in excess of 10 000 operating hours without m a i n t e n a n c e u n d e r normal operating conditions. This corresponds to a continuous, trouble-free operating cycle of well over a year. In i n t e r m i t t e n t service a correspondingly longer service-free operating time can be expected.
The a d v a n c e d 4-layer diaphragm consists of a 2-layer working diaphragm, a monitoring diaphragm and a pressure r e s i s t a n t b a c k -u p d i a p h r a g m which, in c o m b i n a t i o n , allow continued, trouble-free operation of the metering p u m p even when both working diaphragms are ruptured.
A diaphragm r u p t u r e sensor for electric diaphragm rupture signalling or a pressure gauge for visual d i a p h r a g m r u p t u r e detection signal that the diaphragm kit m u s t be replaced within the next few days.
The Lewa ecodos series comprises a total of 3 drive units and 5 p u m p head sizes. Maxi m u m flow rate of 2 to 1500 1/h per p u m p head at p r e s s u r e ranges of 20, 12, 10 and 5 bar are reached by the resulting 12 performance ratings. Up to six pumps, even with different outputs, can be combined into a multiplex pump. The permissible operating t e m p e r a t u r e of the fluids to be metered is -10 to +80ยฐC, viscosities of up to 1000 mPas can be h a n d l e d . Available p u m p head materials are stainless steel 1.4571 (316 Ti), PVC or PVDF.
A d j u s t m e n t of the metered flow is possible via the stroke l e n g t h (by a h a n d w h e e l or stroke a d j u s t m e n t actuator) as well as via the stroke frequency or both parameters. The recomm e n d e d a d j u s t m e n t range by stroke length is 5 : 1, adjustm e n t by stroke frequency in-